SUSE Manager - Sizing and Scaling

This document describes basic hints how to scale and prepare the database.

Clustering and high availability

Purpose

Patching your systems on time is a very important. This document helps with the suggestions how to improve high availability of SUSE Manager appliance.

IMPORTANT: This page contains only friendly hints that can be used when considering cluster setup of SUSE Manager and this information is not an officially supported manual.

Use these suggestions on your own risk and responsibility.

Limitations

WARNING: As of version 1.7 and older, the SUSE Manager is not cluster-aware application. That means that itself it cannot be installed on a several nodes and then joined together as one piece of software. This limitation applies to all product versions and combinations. If customers still wants to do that, it is exclusively ON THEIR OWN RISK AND RESPONSIBILITY.

Stand-by setup

This is nor cluster neither grid setup, but just high availability setup, where SUSE Manager application will be available in partial disaster. In this setup two SUSE Manager appliances are installed as active and passive. Active is what is mainly used, passive is trying to be synchronized as close as possible to the active. Disaster assumes that only one can be down at the time, while another one becomes an active appliance. After the restoration works has been done, restored appliance supposed to be synchronized to the current status.

This method is trying to help to do not lose the data in the database. In case you use an embedded database that comes in SUSE Manager appliance, you probably may consider this method.

SUSE suggests:However, instead of trying keep two SUSE Managers in a sync and hope (crossing fingers) they stay identical even being outside of round-robin access flow, better make sure you can restore a single SUSE Manager appliance from the hot backup (this is supported since version 1.7) as soon as possible. Practically this would mean that the SUSE Manager is not some sort of a mission-critical banking application. Remember that your systems in the Data Center are supposed to get upgraded in the UAT first! That directly means that your production environment can wait "few hours" after you restore your completely destroyed appliance, if such disaster occurs.

Redundant storage

As the SUSE Manager is based on Spacewalk, it acquired its inability to perform on a real cluster and thus is not cluster-aware application. Therefore for High Availability right now the only way is to put database tablespace on redundant shared storage and make sure data stays there rock-solid.

SUSE suggests:It is better to install SUSE Manager on a virtual machine and snapshot the installed working image every time it gets updated itself. Then when SUSE Manager node fails (hardware failure), the same image can be fired up in minutes on different hardware, using HA. That said, instead of by HA SLES extension take care of particular component, say Tomcat or OSAD within the SUSE Manager, it is better to take care the entire virtual machine is running. So if a virtual machine "A1" fails on box "A", SLES HA Extension will start a virtual machine "B1" on a physical box "B" from the same snapshot of the same identical virtual machine.

SLES HA extension

Sinse SUSE Manager is not cluster aware application, therefore the only way that would help here is to automate active/passive scenario. HA extension for SLES will automatically start the rest of the services on passive machine. However, the database needs to be shared. Basically this works in the following way:

"Active" and "Passive" node has an additional link for heartbeat. So when "Active" node breaks, the "Passive" does not receives the heartbeat and thus fires up the application, which connects to the database. This is all done automatically.

Scaling

SUSE Manager can handle about 30,000 servers with a fairly reasonable performance. However, traffic for package repositories could be an issue.

SUSE suggests:It is a very good idea to setup SUSE Manager Proxy per each 5,000 server to offload server traffic from the SUSE Manager in case of packages transfer. This will not add processing performance, but will decrease traffic.

Database Sizing

While it may be used less than that, the SUSE Manager requires to make sure 25GB free disk space is available for most installations. And that still depends on the initial load, which can grow easily grow up to terabyte, if there are many transactions. However, as a rule of thumb, 25GB should be fine.

Tablespace management with Oracle database

Tablespace management is a critical part of database. This section describes tablespace-related enhancements.

In Oracle database the space is usually allocated after a scanning of a bitmap in a header of the data file. There are two types of managed tablespaces that are managed locally. These types are different in the implementation:

Uniform extent allocation. This method uses extents of the same size for all objects within the tablespace.

Automatic extent allocation. This method uses a set of extent sizes that are factors of each other, beginning with 64K and moving upward through 1MB, 8MB, and 64MB.

SUSE Manager as of version 1.7 is using second method to make sure system administrators spend more time with their families, rather then looking after Oracle software. :-) But because of this method, SUSE Manager easily can grow very quickly its database, especially on init run. The database size is not always fixed and space is reclaimed back, archive logs are purged after each backup etc. However there should be enough space to handle a big load of servers, since each transaction also grows space in the archive log until backup is taken.

Keep in mind, the database storage needs may grow rapidly, depending upon the variance of the following factors:

The number of public Vendor packages imported (typical: 5000)

The number of private packages to be managed (typical: 500)

The number of systems to be managed (typical: 1000)

The number of packages installed on the average system (typical: 500)

Although you should be generous in your database sizing estimates, you must consider that size affects the time to conduct backups and adds load to other system resources. If the database is shared, its hardware and spacing are entirely dependent on what else is using it.

SUSE suggests:Put database tablespace on the disk space that can be resized (LVM or BTRFS, ZFS — depends on the storage vendor).

Tablespace management with PostgreSQL database

Despite of its huge elephant logo, PostgreSQL database is still few orders of magnitude less eager for the disk space than its "red colleague" from the California, and thus hardly exceeds 10GB of the disk space even of pretty big amount of handled servers.

SUSE suggests:Put database tablespace on the disk space that can be resized (LVM or BTRFS, ZFS — depends on the storage vendor).

Oracle cold backups

Note: Doing hot backups with SMDBA is strongly preferred. If you still want to do cold backups of your embedded
Oracle database, here's how:

stop the database (smdba db-stop)

Copy away the database files located at /opt/apps/oracle/oradata/susemanager and /opt/apps/oracle/flash_recovery_area/susemanager

Start the database again (smdba db-start)

Database management with SMDBA

SUSE Manager as of version 1.7 has new feature, called SMDBA. The SMDBA is SUSE Manager database control tool and replaces RedHat's "Dobby". This tool is developed to provide the same interface for Oracle and PostgreSQL databases. The set of commands may differ, since database engines are really different and not everything what is in Oracle is in PostgreSQL (and vice versa). SMDBA is used to take hot backups, restore from the complete disaster, check available space, start, stop or restart database etc.

What SMDBA is not

If you use SMDBA for anything else than database administration on a particular appliance, then you do it wrong.

IMPORTANT: Do NOT use SMDBA as database clone tool! If you want to setup several same SUSE Manager instances, setup it on a virtual machine and simply reuse the image.

What taking hot backups...

Please keep in mind that SMDBA can restore only the backups that has been previously taken with it. If you have a backup that you've done yourself, you are likely going to restore your database from that backup completely by yourself.

SMDBA is supposed to control everything or nothing.

Future

SMDBA is going to "dissolve" from the command line in a future versions of SUSE Manager and become completely transparent robotic task, exposing feedback to general logs and WUI.